The present invention relates generally to equipment utilized and operations performed in conjunction with a subterranean well and, in an embodiment described herein, more particularly provides a circulation control valve and associated method.
It is frequently beneficial to be able to selectively permit and prevent circulation flow through a sidewall of a tubular string in a well. For example, at the conclusion of a cementing operation, in which the tubular string has been cemented in the well, it is sometimes desirable to circulate cement out of a portion of an annulus exterior to the tubular string. As another example, in staged cementing operations it may be desirable to flow cement through sidewall openings in a tubular string. Numerous other examples exist, as well.
Although circulation control valves for these purposes have been used in the past, they have not been entirely satisfactory in their performance. For example, one circulation control valve includes multiple rupture disks which are ruptured by internal pressure in order to provide fluid communication through the rupture disks between the annulus and the interior of the valve. However, if all of the rupture disks do not rupture (which will frequently be the case if rupturing of the first disks relieves the internal pressure), then the flow area between the annulus and the interior of the valve will be substantially reduced.
Therefore, it may be seen that improvements are needed in the art of circulation control valves and associated methods.